Driving assistance apparatus

ABSTRACT

A driving assistance apparatus includes a proximity detection section that detects an obstacle within a set distance, a behavior regulation section that performs a forced braking of a vehicle when the obstacle is detected by the proximity detection section, an arrangement memory that stores a past captured image around a target parking region, a captured image acquisition section that acquires a present captured image around the target parking region at parking or departing with respect to the target parking region, and an obstacle specification section that specifies a non-stationary obstacle around the target parking region, based on a difference between the past captured image stored in the arrangement memory and the present captured image acquired by the arrangement acquisition section. The proximity detection section assigns a stationary object with the set distance that is smaller than the set distance assigned to a non-stationary object.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase Application under 35 U.S.C.371 of International Application No. PCT/JP2015/002660 filed on May 26,2015 and published in Japanese as WO 2015/190051 A1 on Dec. 17, 2015.This application is based on and claims the benefit of priority fromJapanese Patent Application No. 2014-119945 filed on Jun. 10, 2014. Theentire disclosures of all of the above applications are incorporatedherein by reference.

TECHNICAL FIELD

The present disclosure relates to a driving assistance apparatus whichcontrols a vehicle according to presence of an obstacle.

BACKGROUND ART

There is conventionally known a technology that detects an obstacleusing such obstacle sensors as a camera or sonar provided in a vehicleand controls the vehicle according to the presence of the obstacle.

For example, Patent literature 1 discloses a driving assistanceapparatus that detects an obstacle within a detection distance based onoutput signals of clearance sonars installed in a front portion and rearportion of the vehicle and sounds a buzzer alarm to output a buzzersound according to the detection distance.

In addition, Patent literature 2 discloses an obstacle determinationapparatus that drives a brake actuator of a vehicle to perform forcedbraking when the distance to the obstacle measured by a radartransitions from above a predetermined value into below thepredetermined value under the situation where the vehicle moves from thestopping state to the departing state.

PRIOR ART LITERATURES Patent Literature

Patent literature 1: JP 2011-126337 A

Patent literature 2: JP 2004-106701 A

SUMMARY OF INVENTION

The driving assistance apparatus in Patent literature 1 however involvesthe following issue. Suppose that a stationary obstacle (hereinafter, astationary object) such as a wall is existing around a parking region athome, e.g., so that the host vehicle needs to always approach closelythe stationary object on each parking or departing. In such cases, thestationary object is always located within the detection distance oneach parking or departing, generating the buzzer sound. The driver ofthe vehicle may be accustomed to parking or departing in the parkingregion and able to perform each parking or departing without no contactwith such a stationary obstacle. Even in such cases, the buzzer sound isgenerated against the stationary object on each parking or departing,causing the driver to feel troublesome.

In addition, Patent literature 2 discloses a technology that performsforced braking on each departing from a parking region at home, e.g., ifa stationary object such as wall is existing in front of the parkingregion and the vehicle needs to always approach closely the stationaryobject. Even if the driver is accustomed to departing from the parkingregion and able to perform each departing without no contact with thestationary obstacle, the forced braking is generated to thereby causethe driver to feel troublesome.

It is an object of the present disclosure to provide a drivingassistance apparatus that performs a report or an automatic behaviorcontrol of a vehicle depending on presence of an obstacle to helpprevent a driver from feeling troublesome even when the vehicle needs toalways approach closely a stationary obstacle that is existing around aparking region on each parking or departing.

According to an example of the present disclosure, a driving assistanceapparatus used in a vehicle is provided to include a control targetdetection, an obstacle handling section, an arrangement memory, anarrangement acquisition section, and an obstacle specification section.The control target detection section detects as a target obstacle anobstacle that is existing within a set distance from the vehicle usingan obstacle sensor detecting an obstacle around the vehicle. Theobstacle handling section performs at least either a report or anautomatic behavior control of the vehicle when the control targetdetection section detects the target obstacle. The arrangement memorystores a past obstacle arrangement around a parking region that servesas a target. The arrangement acquisition section acquires a presentobstacle arrangement around the parking region in a parking-regiondriving operation. The parking-region driving operation is at leasteither a driving operation to cause the vehicle to enter into theparking region or a driving operation to cause the vehicle to exit fromthe parking region. The obstacle specification section specifies anon-stationary obstacle that is an obstacle being not stationary aroundthe parking region, based on a difference between the past obstaclearrangement stored in the arrangement memory and the present obstaclearrangement acquired by the arrangement acquisition section. The controltarget detection section detects the target obstacle by setting the setdistance in cases that the obstacle specification section fails tospecify a non-stationary obstacle to be smaller than the set distance incases that the obstacle specification section specifies a non-stationaryobstacle.

If only a stationary obstacle is existing around a parking region thatis a target, any difference is not found in between the past obstaclearrangement and the present obstacle arrangement around the parkingregion. In contrast, if a non-stationary obstacle is existing, adifference is found in between the past obstacle arrangement and thepresent obstacle arrangement around the parking region. The differencebetween the past obstacle arrangement stored in the arrangement memoryand the present obstacle arrangement acquired by the arrangementacquisition section allows the obstacle specification section to specifya non-stationary obstacle that is an obstacle not stationary around theparking region.

In addition, the control target detection section sets the set distancein cases that any non-stationary obstacle is not specified to be smallerthan the set distance in cases that a non-stationary obstacle isspecified. Even if a stationary obstacle, which the vehicle needs toalways approach closely on each parking or departing, is existing aroundthe parking region, the distance for detecting such a stationaryobstacle as a target obstacle can be shortened. Shortening the distancefor detecting an obstacle as a target obstacle permits the obstacle tobe detected as the target obstacle only when the vehicle approaches theobstacle more closely. Even if the vehicle needs to always approachclosely a stationary obstacle on each parking or departing, any reportor automatic behavior control of the vehicle can be prevented fromworking against the stationary obstacle.

Thus, even if there is existing around a parking region a stationaryobstacle the vehicle needs to always approach closely on each parking ordeparting, the driving assistance apparatus performs a report or anautomatic behavior control of the vehicle depending on presence of thestationary obstacle, helping prevent the driver from feelingtroublesome.

BRIEF DESCRIPTION OF DRAWINGS

The above and other objects, features and advantages of the presentdisclosure will become more apparent from the following detaileddescription made with reference to the accompanying drawings. In thedrawings:

FIG. 1 is a block diagram illustrating an example of a schematicconfiguration of a driving assistance system;

FIG. 2 is a block diagram illustrating an example of a schematicconfiguration of a driving assistance ECU;

FIG. 3 is a flowchart illustrating an example of a sequence of anobstacle learning process in the driving assistance ECU;

FIG. 4 is a diagram illustrating an example of a correspondence relationbetween captured images and patterns of vehicle's parking or departingdirections against a target parking region;

FIG. 5 is a flowchart illustrating an example of a sequence of a parkingor departing assistance process in the driving assistance ECU;

FIG. 6 is a flowchart illustrating an example of a sequence of anobstacle handling process according to the first embodiment;

FIG. 7 is a diagram schematically illustrating examples of a detectionrange detecting a stationary object as a target obstacle using astationary object set distance and a detection range detecting anon-stationary object as a target obstacle using a non-stationary objectset distance;

FIG. 8 is a schematic diagram illustrating an example in which anynon-stationary object does not exist around a target parking region;

FIG. 9 is a schematic diagram illustrating an example in which anon-stationary object exists around same the target parking region as inFIG. 8;

FIG. 10 is a flowchart illustrating an example of a sequence of anobstacle handling process according to a first modification example;

FIG. 11 is a block diagram for explaining a schematic configuration of adriving assistance ECU according to a second modification example;

FIG. 12A is a diagram illustrating an example of a correspondencerelation between captured images and patterns of vehicle's parking ordeparting directions depending on drivers and target parking regionsaccording to the second modification example;

FIG. 12B is a diagram illustrating an example of a correspondencerelation between captured images and patterns of vehicle's parking ordeparting directions depending on drivers and target parking regionsaccording to the second modification example; and

FIG. 13 is a block diagram illustrating an example of a schematicconfiguration of a driving assistance system according to a seventhmodification example.

EMBODIMENTS FOR CARRYING OUT INVENTION First Embodiment

<Schematic Configuration of Driving Assistance System 100>

FIG. 1 is a diagram illustrating an example of a schematic configurationof a driving assistance system 100 which the present disclosure isapplied to. The driving assistance system 100, which is mounted in avehicle, includes a camera 1, a vehicle state sensor group 2, anavigation apparatus 3, a display apparatus 4, a sound output apparatus5, a driving assistance ECU 6, a brake ECU 7, a brake actuator 8, anEPS_ECU 9, and an EPS actuator 10, as illustrated in FIG. 1.Hereinafter, the vehicle mounted with the driving assistance system 100may be also referred to as a host vehicle or a subject vehicle.

The camera 1, which is installed in the vehicle, captures an image of avehicle's peripheral area surrounding the vehicle. The camera 1 may bealso referred to as an obstacle sensor or an imaging apparatus. Thecamera 1 in the present embodiment is explained as an example using afront camera and a rear camera. The front camera captures an image of anarea in front of the vehicle with a predetermined view angle containinga corner portion in a front portion of the vehicle. The rear cameracaptures an image of an area behind the vehicle with a predeterminedview angle containing a corner portion in a rear portion of the vehicle.The camera 1 will be explained as a stereo camera as an example of thepresent embodiment.

The vehicle state sensor group 2 is a various sensor group that detectvehicle states of the vehicle. The vehicle state sensor group 2 includesa vehicle velocity sensor that detects a velocity of the vehicle; ashift position sensor that detects a shift position of the vehicle; anda steer angle sensor that detects a steer angle of the vehicle.

The navigation apparatus 3 includes a position detection unit 31 and amap DB (database) 32. The position detection unit 31 detects a presentposition of the vehicle consecutively, for example, using a positioningsystem which detects the present position of the vehicle based onelectric waves from positioning satellites. The present position of thevehicle is a position of a rear wheel axle of the vehicle indicated bycoordinates of latitude and longitude, for instance. The map DB 32stores map data containing road data including node data and link data.Nodes each correspond to an on-road point such as an intersection,branching point, or joining point that divides each road on anelectronic map; links each connect nodes.

The display apparatus 4 displays texts and images according toinstructions by the driving assistance ECU 6. The display apparatus 4,which can display full colors, includes a liquid crystal display. Thedisplay apparatus 4 may include a display provided in an instrumentpanel or a HUD (head-up display). The sound output apparatus 5 includesa speaker and outputs speeches according to instructions by the drivingassistance ECU 6. The display apparatus 4 or the sound output apparatus5 may be also referred to as a report apparatus.

The brake ECU 7 decelerates the vehicle by controlling the brakeactuator 8 which applies braking force to the vehicle. The EPS_ECU 9controls a steer angle by operating the EPS actuator 10.

The driving assistance ECU 6 mainly includes a microcomputer containinga known CPU, memories such as ROM or RAM, I/O, and a bus connecting theforegoing components. The driving assistance ECU 6 executes variousprocessing based on a variety of information inputted from the camera 1,the vehicle state sensor group 2, and the navigation apparatus 3. Thedriving assistance ECU 6 may be also referred to as a driving assistanceapparatus.

All or part of the functions executed by the driving assistance ECU 6may be configured as hardware components such as one or more ICs.

<Detailed Configuration of Driving Assistance ECU 6>

As in FIG. 2, the driving assistance ECU 6 includes a captured imageacquisition section 61, a target parking region specification section62, a parking region memory 63 (which may be also referred to as aparking region storage portion), a learning determination section 64, apattern specification section 65, an arrangement memory 66 (which may bealso referred to as an arrangement storage portion), an arrangementstorage section 67 (which may be also referred to as an arrangementstorage processing section), an assistance determination section 68, anold and new comparison section 69, an obstacle specification section 70,a proximity detection section 71 (which may be referred to as adetection section), a report section 72 (which may be referred to as areport processing section), and a behavior regulation section 73 (whichmay be also referred to as a behavior control section).

The captured image acquisition section 61 acquires a captured image thatis captured by the camera 1 successively. The target parking regionspecification section 62 specifies a parking region (hereinafter, atarget parking region), which serves as a target for providingassistance at time of parking or departing, and stores the position ofthe specified target parking region in the parking region memory 63. Theposition of the target parking region is indicated with the coordinatesof latitude and longitude, for example.

One example of the target parking region may be a position registered inthe navigation apparatus 3 as user's home. Further, another example ofthe target parking region may be a vehicle position when a usermanipulates a switch such as a button (unshown) for designating thetarget parking region. Yet further, another example of the targetparking region may be a position where the vehicle is parked three timesor more. The vehicle's parking (i.e., parking the vehicle) may bedetermined by the driving assistance ECU 6 based on that the vehiclestate sensor group 2 detects that the shift position has moved to theparking position.

The parking region specification section 62 may specify several targetparking regions like a parking region at home and a parking region atoffice. In such cases, the parking region memory 63 stores severalpositions of the respective target parking regions.

The learning determination section 64, the pattern specification section65, the arrangement memory 66, the arrangement storage section 67, theassistance determination section 68, the old and new comparison section69, the obstacle specification section 70, the proximity detectionsection 71, the report section 72, and the behavior regulation section73 will be explained later in detail.

<Obstacle Learning Process in First Embodiment>

The following explains an obstacle learning process by the drivingassistance ECU 6 with reference to the flowchart in FIG. 3. The obstaclelearning process is to store an obstacle arrangement that is anarrangement of obstacle(s) around a target parking region. The flowchartin FIG. 3 is started when the ignition power source of the vehicle isturned into ON state.

It is further noted that a flowchart or processing of the process in thepresent disclosure includes sections (also referred to as steps), whichare represented, for instance, as S1. Further, each section can bedivided into several sections while several sections can be combinedinto a single section. Furthermore, each section can be referred to as adevice or module. Further, each section or combined sections can beachieved not only (i) as a software section in combination with ahardware unit (e.g., computer), but also (ii) as a hardware section(e.g., integrated circuit, hard-wired logic circuit), including or notincluding a function of a related apparatus. Further, the hardwaresection may be inside of a microcomputer.

First, at S1, the learning determination section 64 determines whetherthe vehicle starts either a driving operation to cause the vehicle toenter the target parking region or a driving operation to cause thevehicle to exit from the target parking region (hereinafter, parking ordeparting). For instance, that the vehicle starts parking to the targetparking region may be determined when the followings are simultaneouslysatisfied: the distance between the present position of the vehicle andthe position of the target parking region stored in the parking regionmemory 63 being less than a predetermined distance such as 15 m, forexample; the shift position of the vehicle detected by the vehicle statesensor group 2 being not the parking position; and the vehicle speeddetected by the vehicle state sensor group 2 being equal to or less thana vehicle speed going slowly, for instance. Further, that the vehiclestarts departing from the target parking region may be determined whenthe followings are simultaneously satisfied: the distance between thepresent position of the vehicle and the position of the target parkingregion being less than the predetermined distance; and the shiftposition of the vehicle detected by the vehicle state sensor group 2being moved from the parking position to the forward moving position orthe backward movement position.

In addition, another condition may be added such as the steer angle ofthe vehicle detected by the vehicle state sensor group 2 varying by apredetermined value or more.

When starting of the parking or departing is determined (S1: YES), theprocessing moves to S2. When starting of the parking or departing is notdetermined (S1: NO), the processing moves to S6.

At S2, the pattern specification section 65 specifies a patternaccording to a state of the vehicle. The following explains the cases ofspecifying the patterns of parking or departing directions of thevehicle with respect to the target parking region, as an example of thepresent embodiment. The patterns of the parking or departing directionsof the vehicle with respect to the target parking region may bespecified from the present position of the vehicle, the headingdirection of the vehicle using the present position of the vehicleobtained successively, the link data, and the target parking region.

The patterns of parking or departing directions of the vehicle withrespect to the target parking region include twelve patterns as in FIG.4, as follows: “entering from the right with backward movement,”“entering from the left with backward movement,” “entering straight withbackward movement,” “entering from the right with forward movement,”“entering from the left with forward movement,” “entering straight withforward movement,” “exiting to the right with backward movement,”“exiting to the left with backward movement,” “exiting straight withbackward movement,” “exiting to the right with forward movement,”“exiting to the left with forward movement,” and “exiting straight withforward movement.” FIG. 4 is a diagram illustrating an example of acorrespondence relation between captured images and patterns ofvehicle's parking or departing directions with respect to a targetparking region. The correspondence relation is stored in the arrangementmemory 66 with respect to each target parking region. FIG. 4 illustratesthe correspondence relation between captured images and patterns ofvehicle's parking or departing directions with respect to the targetparking region C.

At S3, the arrangement storage section 67 determines whether a capturedimage about the pattern specified at S2 is previously stored in thearrangement memory 66. Suppose that the past obstacle learning processstored the captured image about the corresponding pattern. In such acase, the captured image about the pattern specified at S2 is previouslystored in the arrangement memory 66. In contrast, suppose that theobstacle learning process is performed for the first time so that anycaptured image about the corresponding pattern is not stored. In such acase, the captured image about the pattern specified at S2 is notpreviously stored in the arrangement memory 66.

When it is determined that the captured image is not stored (S3: NO),the processing moves to S4. At S4, the captured image acquisitionsection 61 acquires a captured image. The acquired captured image isthen stored by the arrangement storage section 67 in the arrangementmemory 66 to be associated with the pattern specified at S2 (see FIG.4), terminating the obstacle learning process. The captured imageacquired by the captured image acquisition section 61 is acquired by thecamera 1 capturing an image of an area in the heading direction of thevehicle. That is, the front camera acquires the captured image inforward movement; the rear camera acquires the captured image inbackward movement.

Here, the associated patterns of “entering from the right with backwardmovement” and “entering from the right with forward movement” providerespective captured images similar to each other. Similarly, theassociated patterns of “entering from the left with backward movement”and “entering from the left with forward movement” provide respectivecaptured images similar to each other. The associated patterns of“entering straight with backward movement” and “entering straight withforward movement” provide respective captured images similar to eachother. The associated patterns of “exiting to the right with backwardmovement” and “exiting to the right with forward movement” providerespective captured images similar to each other. The associatedpatterns of “exiting to the left with backward movement” and “exiting tothe left with forward movement” provide respective captured imagessimilar to each other. The associated patterns of “exiting straight withbackward movement” and “exiting straight with forward movement” providerespective captured images similar to each other. When a subjectcaptured image is acquired for one pattern of the associated patterns,the subject captured image may be stored also for the other pattern ofthe associated patterns.

When it is determined that the captured image is already stored (S3:YES), the processing moves to S5. At S5, the arrangement storage section67 determines whether the captured image stored in the pattern specifiedat S2 needs to be updated. For instance, the captured image needs to beupdated when any non-stationary object that is not stationary is notspecified from the captured image acquired by the captured imageacquisition section 61 at S27 of the parking or departing assistanceprocess executed in parallel with the obstacle learning process, forinstance. The parking or departing assistance process will be explainedlater.

When it is determined that the captured image needs to be updated (S5:YES), the processing moves to S4. At S4, the captured image acquired bythe captured image acquisition section 61 is written over thearrangement memory 66 by the arrangement storage section 67 to beassociated with the pattern specified at S2, thereby performing theupdate of the captured image. In contrast, when it is not determinedthat the captured image needs to be updated (S5: NO), the processingmoves to S6.

The above explains the configuration that determines whether thecaptured image needs to be updated; however, another configuration maybe provided which always updates the captured image without determiningwhether to need to be updated.

At S6, when it is determined that the time for terminating the obstaclelearning process comes (S6: YES), the obstacle learning process isterminated. In addition, when it is not determined that the time forterminating the obstacle learning process comes (S6: NO), the processingreturns to S1 to repeat the process. An example of the time forterminating the obstacle learning process may be the time when thedistance between the present position of the vehicle and the position ofthe target parking region stored in the parking region memory 63 beingequal to or greater than the predetermined distance, or the time whenthe ignition power source of the vehicle is turned into OFF state.

<Parking or Departing Assistance Process in First Embodiment>

The following explains a parking or departing assistance process by thedriving assistance ECU 6 with reference to the flowchart in FIG. 5. Theparking or departing assistance process performs a report or a vehiclebehavior control according to an obstacle closely approaching thevehicle at the time of parking or departing with respect to the targetparking region. The flowchart in FIG. 5 is started when the ignitionpower source of the vehicle is turned into ON state, and is executed inparallel with the above-mentioned obstacle learning process.

First, at S21, similarly to S1, the assistance determination section 68determines whether the vehicle starts either a driving operation tocause the vehicle to enter the target parking region or a drivingoperation to cause the vehicle to exit from the target parking region(i.e., parking or departing). When starting of the parking or departingis determined (S21: YES), the processing moves to S22. When starting ofthe parking or departing is not determined (S21: NO), the processingmoves to S29.

At S22, similarly to S2, the pattern specification section 65 specifiesa pattern according to the state of the vehicle. An example of thepresent embodiment specifies the pattern of parking or departingdirection of the vehicle with respect to the target parking region.

Here, the processing at S21-S22 may use S1-S2 in the obstacle learningprocess executed in parallel with the parking or departing assistanceprocess. In such cases, one of the learning determination section 64 andthe assistance determination section 68 may be provided with thefunction of the other one of the learning determination section 64 andthe assistance determination section 68.

At S23, the arrangement storage section 67 determines whether thecaptured image is stored in the arrangement memory 66 with respect tothe combination of the pattern specified at S22 and the target parkingregion of which parking or departing is determined at S21. In detail,when the captured image of the corresponding pattern is stored by thepast obstacle learning process, it is determined that the captured imageis stored in the arrangement memory 66. When the captured image of thecorresponding pattern is not stored, it is not determined that thecaptured image is stored in the arrangement memory 66. When it isdetermined that the captured image is stored (S23: YES), the processingmoves to S24. When it is determined that the captured image is notstored (S23: NO), the processing moves to S29.

At S24, the captured image acquisition section 61 acquires the presentcaptured image. Therefore, the captured image acquisition section 61 maybe also referred to as an arrangement acquisition section. At S25, thepast captured image stored to be associated with the pattern specifiedat S22 is read out from the arrangement memory 66. The present capturedimage acquired at S24 and the past captured image read from thearrangement memory 66 at S25 have respective patterns identical to eachother in respect of parking or departing direction with respect to thetarget parking region at the time of capturing.

In addition, even when a captured image is stored in the arrangementmemory 66 at S4 of the obstacle learning process currently executed inparallel with the parking or departing assistance process, storing thecaptured image is performed based on the result of the processing at S27after S25. Thus, S25 reads the captured image stored in the arrangementmemory 66 by the past obstacle learning process earlier than theobstacle learning process currently executed in parallel with theparking or departing assistance process.

At S26, the old and new comparison section 69 compares the presentcaptured image acquired at S24 with the past captured image read fromthe arrangement memory 66 at S25, and detects a difference in thecaptured images. Such difference in the captured images may be detectedby subtracting the past captured image from the present captured image,similar to a known temporal difference imaging method, for example.Further, the difference may be detected as being greater than the errorlevel.

The above error level may desirably include an error equivalent to atravel-tracks difference, which arises between the past captured imageand the present captured image due to the deviation between the past andpresent travel tracks even if the same pattern of parking or departingdirection of the vehicle is used. Such configuration can prevent thetravel-tracks difference from being mistaken for the difference betweenthe past captured image and the present captured image, therebyimproving the accuracy for specifying a non-stationary object mentionedlater.

(i) The present captured image acquired at S24 and (ii) the pastcaptured image read from the arrangement memory 66 at S25 are identicalto each other in the pattern of parking or departing with respect to thetarget parking region at the capturing time, each having almostidentical capturing direction and capturing position. The arrangement ofa stationary obstacle thus becomes identical in each of the pastcaptured image and the present captured image. Subtracting the pastcaptured image from the present captured image thus leads to an easydetection of the difference in the captured images.

Further, the capturing direction or the capturing position may bedeviated between the past captured image and the present captured image.To consider such deviation, the influence due to the deviation may bedesirably removed before subtracting the past captured image from thepresent captured image. For instance, several common characteristicpoints may be detected in between the present captured image and thepast captured image; the captured images may be subjected to suchmodifications as enlargement, reduction, or rotation so that thepositions of the several characteristic points overlap. This can removethe influence due to the deviation of the capturing direction orcapturing position.

At S27, the obstacle specification section 70 specifies an obstacle thatis not stationary (i.e., non-stationary object, non-stationary obstacle,or transitory obstacle) and an obstacle that is stationary (i.e.,stationary object, stationary obstacle, or a non-transitory obstacle)around the target parking region based on the difference detected atS26.

One example uses a source image and a distance distribution (i.e.,distance image) to detect several obstacles such as three-dimensionalobject, wall, bicycle, pedestrian in the captured image using a knownimage-recognition process and also detect the distances between thevehicle and the obstacles. The distance image is acquired from theazimuth difference of the present captured image of the stereo camerawith a well-known stereo image process. Of the detected obstacles, anobject existing in a position of the difference detected at S26 isspecified as a non-stationary object; an object existing at a positionother than the position of the difference detected at S26 is specifiedas a stationary object.

In addition, the obstacle specification section 70 detects successivelydistances between the vehicle and the stationary objects ornon-stationary objects based on the distance image obtained from thecaptured images successively captured by the captured image acquisitionsection 61. Once specifying a stationary object or non-stationaryobject, the obstacle specification section 70 may detect successivelythe distance between the vehicle and the stationary object ornon-stationary object by tracing the position of the stationary objector non-stationary object in the captured image with a known regiontracking process, without repeatedly specifying the stationary object ornon-stationary object.

At S28, an obstacle handling process is executed. The following explainsan obstacle handling process with reference to a flowchart in FIG. 6.

First, at S281, when the obstacle(s) specified by the obstaclespecification section 70 are each only a stationary object among astationary object and a non-stationary object (S281: YES), theprocessing moves to S282. In contrast, when the obstacle(s) specified bythe obstacle specification section 70 includes a non-stationary object(S281: NO), the processing moves to S286.

At S282, the proximity detection section 71 sets a stationary object setdistance to be smaller than a default set distance; the stationaryobject set distance is a set distance for detecting a stationary objectas a target obstacle targeted for a report or a vehicle behaviorcontrol. The stationary object set distance may be also referred to as aset distance.

The default set distance may be set to be used even in a parking regionother than the target parking region for performing a report indicatinga close approach to a target obstacle to a driver or a behavior controlof the vehicle for avoiding contact of the vehicle to a target obstacle.In addition, the default set distance is set to be variable as needed,for instance, depending on the vehicle speed and set to have a greatmargin to the distance necessary for avoiding contact with an obstacle.

In setting the stationary object set distance to be smaller than thedefault set distance, the above-mentioned margin in the default setdistance may be decreased significantly as long as the stationary objectset distance is still longer than the distance necessary for avoidingcontact with an obstacle.

At S283, the proximity detection section 71 detects a stationary objectas a target obstacle when the distance between the vehicle and thestationary object successively detected by the obstacle specificationsection 70 is equal to or smaller than the stationary object setdistance acquired at S282. The proximity detection section 71 may bealso referred to as a control target detection section. When theproximity detection section 71 detects the stationary object specifiedby the obstacle specification section 70 as a target obstacle (S283:YES), the processing moves to S284. In contrast, when not detecting as atarget obstacle (S283: NO), the processing moves to S285.

At S284, a report or a vehicle behavior control is performed. The reportis for indicating a close approach to a target obstacle to a driver; thevehicle behavior control is for avoiding contact of the vehicle to atarget obstacle. For instance, the report section 72 instructs thedisplay apparatus 4 or the sound output apparatus 5 to perform a reportindicating the presence of an obstacle. Further, the behavior regulationsection 73 may instruct the brake ECU 7 to control the brake actuator 8for performing forced braking such as decelerating or stopping thevehicle automatically. Furthermore, the behavior regulation section 73may instruct the EPS_ECU 9 to operate the EPS actuator 10 forcontrolling automatically the steer angle to avoid a target obstacle.The report section 72 and the behavior regulation section 73 may be alsoreferred to as an obstacle handling section.

At S285, the assistance determination section 68 determines whether thevehicle completes parking or departing. For instance, when the distancebetween the present position of the vehicle and the position of thetarget parking region becomes equal to or greater than the predetermineddistance, the vehicle may be determined to have completed departing.When the shift position of the vehicle becomes the parking position, thevehicle may be determined to have completed parking. When parking ordeparting is determined to be completed (S285: YES), the processingmoves to S29. In contrast, when parking or departing is not determinedto be completed (S285: NO), the processing returns to S282 to repeat theprocess.

Further, at S286 after a non-stationary object is determined to beincluded in the obstacle(s) specified by the obstacle specificationsection 70, the proximity detection section 71 sets a non-stationaryobject set distance to be identical to the default set distance; thenon-stationary object set distance is for detecting a non-stationaryobject as a target obstacle. The non-stationary object set distance maybe also referred to as a first set distance.

At S287, the proximity detection section 71 detects a non-stationaryobject as a target obstacle when the distance between the vehicle andthe non-stationary object successively detected by the obstaclespecification section 70 is smaller than the non-stationary object setdistance. When the proximity detection section 71 detects thenon-stationary object specified by the obstacle specification section 70as a target obstacle (S287: YES), the processing moves to S288. Incontrast, when not detecting as a target obstacle (S287: NO), theprocessing moves to S289.

At S288, similarly to S284, a report or a vehicle behavior control isperformed. The report is for indicating a close approach to a targetobstacle to a driver; the vehicle behavior control is for avoidingcontact of the vehicle to a target obstacle. The report or vehiclebehavior control when a target obstacle is a stationary object may bedifferent from the report or vehicle behavior control when a targetobstacle is a non-stationary object.

At S289, similarly to S282, the proximity detection section 71 sets astationary object set distance to be smaller than the default setdistance; the stationary object set distance is for detecting astationary object as a target obstacle.

Here, FIG. 7 is used to schematically illustrate examples of a detectionrange for detecting a stationary object as a target obstacle using astationary object set distance and a detection range for detecting anon-stationary object as a target obstacle using a non-stationary objectset distance. The broken lines in FIG. 7 illustrate detection ranges todetect a target obstacle.

The non-stationary object set distance for a non-stationary object usesthe default set distance; the detection range for detecting anon-stationary object as a target obstacle becomes a detection rangehaving a great margin to the distance necessary for avoiding contactwith an obstacle. In contrast, the stationary object set distance for astationary object has a margin significantly smaller than the margin ofthe default set distance; the detection range for detecting a stationaryobject as a target obstacle becomes smaller than that for detecting anon-stationary object as a target obstacle, as in FIG. 7. This disablesa report or a vehicle behavior control for a stationary object unlessthe vehicle approaches closely the stationary object.

At S290, similarly to S283, when the proximity detection section 71detects the stationary object specified by the obstacle specificationsection 70 as a target obstacle (S290: YES), the processing moves toS291. In contrast, when not detecting as a target obstacle (S290: NO),the processing moves to S292.

At S291, similarly to S284, a report or a vehicle behavior control isperformed. The report is for indicating a close approach to a targetobstacle to a driver; the vehicle behavior control is for avoidingcontact of the vehicle to a target obstacle. At S292, similarly to S285,the assistance determination section 68 determines whether the vehiclecompletes parking or departing. When parking or departing is determinedto be completed (S292: YES), the processing moves to S29. In contrast,when parking or departing is not determined to be completed (S292: NO),the processing returns to S286 to repeat the process.

Returning to FIG. 5, at S29, when it is determined that the time forterminating the parking or departing assistance process comes (S29:YES), the parking or departing assistance process is terminated. Inaddition, when it is not determined that the time for terminating theparking or departing assistance process comes (S29: NO), the processingreturns to S21 to repeat the process. One example of the time forterminating the parking or departing assistance process is the ignitionpower source of the vehicle being turned into OFF state.

<Summary of First Embodiment>

The following explains effects of the first embodiment specificallyusing FIG. 8 and FIG. 9. FIG. 8 is a schematic diagram illustrating anexample in which any non-stationary object does not exist around atarget parking region; FIG. 9 is a schematic diagram illustrating anexample in which a non-stationary object exists around same the targetparking region as in FIG. 8. In FIG. 8 and FIG. 9, A illustrates avehicle, B1 to B6 each illustrate a stationary object, and C illustratesa target parking region; in FIG. 9, D illustrates a non-stationaryobject.

Suppose that the stationary object B1, which the vehicle A needs toalways approach on each parking or departing, is existing around thetarget parking region C, and the distance for detecting the stationaryobject B1 as a target obstacle has a great margin to the distancenecessary for avoiding contact with an obstacle. In such cases, a reporton the stationary object B1 or the behavior control such as forcedbraking of the vehicle A may be performed on each parking or departing.The driver may be accustomed to perform parking or departing in thetarget parking region C and able to perform each parking or departingwithout no contact between the vehicle A and the stationary object B1.Even in such cases, the report on the stationary object B1 or thebehavior control of the vehicle A is performed on each parking ordeparting, causing the driver to feel troublesome.

In contrast, the first embodiment uses the distance having asignificantly smaller margin as the stationary object set distance fordetecting the stationary object B1 as a target obstacle; this candisable a report or behavior control unless the vehicle A approachesclosely the stationary object B1.

Thus, even if there is existing around a parking region a stationaryobstacle the vehicle needs to always approach closely on each parking ordeparting, the driver's troublesomeness due to a report or an automaticbehavior control of the vehicle according to the presence of theobstacle can be decreased.

In addition, the first embodiment uses the distance having asignificantly greater margin as a set distance for detecting thenon-stationary object D, if present, as in FIG. 9. This can assist thevehicle A in parking or departing by performing earlier a report or abehavior control of the vehicle A against the non-stationary object D,which is not noticed by even a driver who is accustomed to parking ordeparting in the target parking region C.

First Modification Example

The above-mentioned embodiment sets a set distance for a non-stationaryobject, and a set distance for a stationary object, separately. There isno need to be limited thereto. For example, a set distance for anon-stationary object may be uniform to a set distance for a stationaryobject, which is referred to as a first modification example. Thefollowing explains the first modification example. To simplify theexplanation of the present modification example or followingmodification examples, an element or component having the same functionas that of the element or component explained in the foregoingembodiment is assigned with the same reference number as that in theforegoing embodiment and omitted from the following explanation.

The driving assistance system 100 of the first modification example isthe same as the driving assistance system 100 of the first embodiment,except that an obstacle handling process in the parking or departingassistance process is partially different from the first embodiment.

<Obstacle Handling Process of First Modification Example>

The obstacle handling process according to the first modificationexample will be explained using a flowchart in FIG. 10.

First, at S281 a, similarly to S281, when the obstacle(s) specified bythe obstacle specification section 70 are each only a stationary object(S281 a: YES), the processing moves to S282 a. In contrast, when anon-stationary object is included in the obstacle(s) specified by theobstacle specification section 70 (S281 a: NO), the processing moves toS283 a.

At S282 a, the proximity detection section 71 sets a set distance to besmaller than a default set distance; the set distance is for detectingan obstacle as a target obstacle targeted for a report or vehiclebehavior control. The default set distance may be identical to thedefault set distance in the first embodiment.

At S283 a, the proximity detection section 71 maintains a set distancefor detecting a target obstacle to be identical to the default setdistance.

At S284 a, the proximity detection section 71 detects a non-stationaryobject as a target obstacle when the distance between the vehicle andthe non-stationary object or stationary object successively detected bythe obstacle specification section 70 is smaller than the set distance.As explained above, when the obstacle(s) specified by the obstaclespecification section 70 are each only a stationary object, the setdistance is used as being smaller than the default set distance. When anon-stationary object is included in the obstacle(s), the default setdistance is used.

When the proximity detection section 71 detects the non-stationaryobject or stationary object specified by the obstacle specificationsection 70 as a target obstacle (S284 a: YES), the processing moves toS285 a. In contrast, when not detecting as a target obstacle (S284 a:NO), the processing moves to S286 a.

At S285 a, similarly to S284, a report or a vehicle behavior control isperformed. The report is for indicating a close approach to a targetobstacle to a driver; the vehicle behavior control is for avoidingcontact of the vehicle to a target obstacle. The report or vehiclebehavior control when a target obstacle is a stationary object may bedifferent from the report or vehicle behavior control when a targetobstacle is a non-stationary object.

At S286 a, similarly to S285, the assistance determination section 68determines whether the vehicle completes parking or departing. Whenparking or departing is determined to be completed (S286 a: YES), theprocessing moves to S29. In contrast, when parking or departing is notdetermined to be completed (S286 a: NO), the processing returns to S284a to repeat the process.

<Summary of First Modification Example>

The configuration of the first modification example uses a distancesmaller than the default set distance as a set distance for detecting anobstacle targeted for a report or a vehicle behavior control when theobject(s) existing around a target parking region are each only astationary object without containing any non-stationary object. This candisable a report or a behavior control against a stationary objectunless the vehicle approaches closely the stationary object.

Thus, even if there is existing around a parking region a stationaryobstacle the vehicle needs to always approach closely on each parking ordeparting, the driver's troublesomeness due to a report or an automaticbehavior control of the vehicle according to the presence of theobstacle can be decreased.

Second Modification Example

The above embodiment stores the captured image corresponding to thepattern according to the state of the vehicle depending on each ofdifferent target parking regions, in the arrangement memory 66, andreads out the past captured image corresponding to the target parkingregion and the pattern according to the state of the vehicle from thearrangement memory 66. There is no need to be limited thereto. Thecaptured image corresponding to the pattern according to the state ofthe vehicle may be stored in the arrangement memory 66, depending oneach of different target parking regions and each of different drivers,and the past captured image corresponding to (i) the driver, (ii) thetarget parking region, and (iii) the pattern according to the state ofthe vehicle may be read out from the arrangement memory 66, which mayreferred to as a second modification example. The following explains thesecond modification example.

The driving assistance system 100 according to the second modificationexample is identical to that in the first embodiment, except that (i)the driving assistance ECU 6 further includes a driver specificationsection 74 which specifies the driver and (ii) the obstacle learningprocess and the parking or departing assistance process are partiallydifferent from those in the first embodiment.

<Detailed Configuration of Driving Assistance ECU 6 According to SecondModification Example>

The following will explain the driving assistance ECU 6 according to thesecond modification example using FIG. 11. FIG. 11 describes onlyfunctional blocks necessary for explaining the second modificationexample out of the functional blocks included in the driving assistanceECU 6, for convenience.

The driving assistance ECU 6 according to the second modificationexample includes the captured image acquisition section 61, the targetparking region specification section 62, the parking region memory 63,the learning determination section 64, the pattern specification section65, the arrangement memory 66, the arrangement storage section 67, theassistance determination section 68, the old and new comparison section69, the obstacle specification section 70, the proximity detectionsection 71, the report section 72, the behavior regulation section 73,and the driver specification section 74.

The driver specification section 74 specifies a driver who is drivingthe vehicle. One example may use a weight scale or a pressure sensorwhich is provided in a seating portion of the driver seat, as thevehicle state sensor group 2, and specify a specific driver from theweight measured with the weight scale, or the detection value with thepressure sensor. Alternatively, an ID received from an electronic keymay be used to specify a specific driver.

<Obstacle Learning Process in Second Modification Example>

In the obstacle learning process according to the second modificationexample, the pattern specification section 65 specifies a patternaccording to the state of the vehicle and, in addition, the driverspecification section 74 specifies a driver driving the vehicle, whenthe learning determination section 64 determines the start of parking ordeparting.

The arrangement storage portion 67 stores the captured image acquired bythe image acquisition section 61 in the arrangement memory 66 to beassociated with the pattern specified by the pattern specificationsection 65 and the driver specified by the driver specification section74. Storing the captured image in the arrangement memory 66 is similarto the obstacle learning process in the first embodiment; thus, suchstoring is conducted when the arrangement storage section 67 determinesthat the captured image of the combination between the pattern specifiedby the pattern specification section 65 and the driver specified by thedriver specification section 74 is needed to be updated or is not storedin the arrangement memory 66.

Storing the captured image in the arrangement memory 66 is conducted, asin FIGS. 12A and 12B, such that the combination of a specific driver(refer to X and Y) and a specific parking region (refer to C1 and C2)are associated with the patterns according to the states of the vehicle.The patterns according to the states of the vehicle in FIGS. 12A and 12Buse the patterns of parking or departing directions of the vehicle withrespect to the target parking region, for example.

An example, where the different target parking regions are assigned torespective drivers using the vehicle, as follows. The wife (Y in FIG.12B) assigns the target parking region to the parking region of thewife's parents' home (C2 in FIG. 12B); in contrast, the husband (X inFIG. 12A) does not assign the target parking region to that of thewife's parents' home (C2 in FIG. 12B).

<Parking or Departing Assistance Process According to SecondModification Example>

In the parking or departing assistance process according to the secondmodification example, when the assistance determination section 68determines that parking or departing is started, the driverspecification section 74 additionally specifies the driver who isdriving the vehicle while the pattern specification section 65 specifiesthe pattern according to the state of the vehicle.

(i) The target parking region in which parking or departing isdetermined to be started, (ii) the pattern specified by the patternspecification section 65, and (iii) the driver specified by the driverspecification section 74 are combined; when the captured image undersuch combination is determined by the arrangement storage section 67 tobe stored in the arrangement memory 66, the stored captured image isread as a past captured image. The past captured image and the presentcaptured image acquired by the captured image acquisition section 61 arecompared with each other by the old and new comparison section 69,detecting a difference between the captured images.

<Summary of Second Modification Example>

A single vehicle may be used by several drivers; a first driver mayassign the target parking region to a subject parking region while asecond driver may not assign the target parking region to the subjectparking region. Even such situation may be handled by the secondmodification example. That is, since the past captured image of thetarget parking region according to a specific driver among the severaldrivers is stored, the set distance for detecting a stationary objecttargeted for a report or forced braking can be set to be smaller in thetarget parking region according to the specific driver.

The effects by the configuration of the second modification example willbe explained by using the example, where the wife (Y in FIG. 12B)assigns the target parking region to the parking region of the wife'sparents' home (C2 in FIG. 12B); in contrast, the husband (X in FIG. 12A)does not assign the target parking region to that of the wife's parents'home (C2 in FIG. 12B). In addition, similarly in the parking region C inFIG. 8, the wall is very close to the departing direction of the vehiclein the parking region C of the wife's parents' home; the vehicle needsto approach closely the wall on each departing. However, the wife Y, whois accustomed to departing from the parking region C, can depart withoutmanipulating both forward movement and backward movement with a steeringwheel turned. In contrast, the husband X, who is not accustomed todeparting from the parking region C, cannot depart without manipulatingboth forward movement and backward movement with the steering wheelturned.

Under such situation, when the wife Y is the driver, the parking regionC2 corresponds to the target parking region; the set distance fordetecting a stationary object as a target for forced braking is set asbeing smaller. This can prevent the forced braking from working due tothe presence of the wall even though the wife can depart from theparking region C2 without manipulating both forward movement andbackward movement with the steering wheel turned. The wife Y can beprevented from feeling troublesome due to the forced braking.

In contrast, when the husband X is the driver, the parking region C2does not correspond to the target parking region; the set distance fordetecting not only a non-stationary obstacle but also a stationaryobject as a target for forced braking is not set as being smaller. Thiscan allow the husband X to receive an assistance that activates theforced braking of the vehicle when approaching closely the wall; thehusband X can depart from the parking region C2 without contact of thevehicle to the wall although the husband X is unfamiliar. Thus, theconfiguration of the second modification example can provide assistancenecessary for a specific driver.

Third Modification Example

The above embodiment explains an example where the patterns according tothe states of the vehicle use the patterns of parking or departingdirections of the vehicle with respect to the target parking region.There is no need to be limited thereto. The patterns according to thestates of the vehicle may be patterns of time zones or weather, whichmay be referred to as a third modification example.

The patterns of the time zones or weather may be patterned with daytimeor night, or patterned with fair, cloudy, rainy, snowy, etc. Suchpatterns only need to be classified with differences which prevent aspecific obstacle from being recognized as being identical on thecaptured images.

The third modification example can specify a non-stationary object fromthe present captured image and the past captured image that have thesame condition in time zone or weather, eliminating the influence of theerroneous decision arising when the conditions such as time zone orweather are different. The non-stationary object may be specified withmore sufficient accuracy.

Fourth Modification Example

In addition, the pattern according to the state of the vehicle may usethe distance of the vehicle to the target parking region. The patternsof the distance of the vehicle to the target parking region may beseveral levels, which may be referred to as a fourth modificationexample.

The number of obstacles captured in the present captured image and thepast captured image may differ due to the significant difference in thedistance of the vehicle to the target parking region even if the numberof the obstacles actually existing is the same in the present and thepast. This lowers the accuracy of specifying a non-stationary object.

The fourth modification example can respond thereto. That is, anon-stationary object can be specified from the past and presentcaptured images captured when the conditions in the distance of thevehicle to the target parking region are the same, eliminating theinfluence of the erroneous decision produced when the distances of thevehicle to the target parking region differ from each othersignificantly. The non-stationary object may be specified with moresufficient accuracy.

Fifth Modification Example

The above embodiment explains the configuration in which the setdistance about a non-stationary object or the set distance in cases thata non-stationary object is existing is maintained to be identical to thedefault set distance; and the set distance about a stationary object orthe set distance in cases that any non-stationary object is not existing(i.e., in cases that only stationary object(s) is existing) is varied tobe smaller than the default set distance. There is no need to be limitedthereto.

Another configuration may be provided as long as the following relationis satisfied. That is, the set distance about a non-stationary object orthe set distance in cases that a non-stationary object is existing ismaintained to be greater than the set distance about a stationary objector the set distance in cases that any non-stationary object is notexisting. For instance, the set distance about a stationary object orthe set distance in cases that any non-stationary object is not existingis maintained to be identical to the default set distance; in contrast,the set distance about a non-stationary object or the set distance incases that a non-stationary object is existing is varied to be greaterthan the default set distance.

Sixth Modification Example

The above-mentioned embodiment explains using as the camera 1 both thefront camera and the back camera. There is no need to be limitedthereto. For example, only the front camera among the front camera andback cameras may be used as the camera 1, or only the back camera may beused.

For example, the configuration using only the front camera may apply tothe case of exiting from the target parking region with forward movementor the case of entering into the target parking region with forwardmovement in the present disclosure; the configuration using only theback camera may apply to the case of exiting from the target parkingregion with backward movement or the case of entering into the targetparking region with backward movement in the present disclosure.

Seventh Modification Example

The above embodiment explains the configuration in which the camera 1has both the sensor for storing and comparing the arrangement ofobstacle(s) and the sensor for detecting the distance to obstacles.There is no need to be limited thereto. For instance, anotherconfiguration may be provided which uses a sensor for storing andcomparing the arrangement of obstacle(s) and a different sensor fordetecting the distance to obstacles, which may be referred to as aseventh modification example. The following will explain the case wherethe camera 1 is used as the sensor for storing and comparing thearrangement of obstacle(s) while an ultrasonic sensor 11 is used as thedifferent sensor for detecting the distance to obstacles, which may bereferred to as a sixth modification example.

The driving assistance system 100 a of the seventh modification exampleis the same as the driving assistance system 100 of the firstembodiment, except that the ultrasonic sensor 11 is included and theparking or departing assistance process in the driving assistance ECU 6is partially different from that of the first embodiment.

<Schematic Configuration of Driving Assistance System 100 a>

The driving assistance system 100 a, which is mounted in a vehicle,includes a camera 1, a vehicle state sensor group 2, a navigationapparatus 3, a display apparatus 4, a sound output apparatus 5, adriving assistance ECU 6, a brake ECU 7, a brake actuator 8, an EPS_ECU9, an EPS actuator 10, and an ultrasonic sensor 11, as in FIG. 13.

The ultrasonic sensor 11, which is installed in the vehicle, detects thedistance to an obstacle around the vehicle. The ultrasonic sensor 11 mayalso be referred to as an obstacle sensor. The following will explainthe case of using, as the ultrasonic sensor 11, a plurality ofultrasonic sensors 11 provided in front portions of the vehicle ashaving as a scanning region a predetermined angle region in front of thevehicle including front corner portions, and a plurality of ultrasonicsensors 11 provided in rear portions of the vehicle as having as ascanning region a predetermined angle region behind the vehicleincluding rear corner portions.

The configuration using the ultrasonic sensors 11 will be explained;alternatively, another configuration using a different sensor such as aradar other than the ultrasonic sensors may be provided as far as thedifferent sensor detects the distance between the vehicle and anobstacle based on the delay time between the transmission and receptionwaves of the search waves.

In addition, the driving assistance ECU 6 of the seventh modificationexample may provide the configuration where the position of the obstaclerelative to the vehicle is detected through triangular surveying fromthe distance between the vehicle and the obstacle detected by theplurality of ultrasonic sensors 11. Further, when the radar is used inplace of the ultrasonic sensors 11, the radar may be of a phasemono-pulse system. That is, the position of the obstacle relative to thevehicle may be detected from the orientation of the obstacle relative tothe vehicle which is found from the phase difference of the transmissionand reception waves of the search waves, and the distance which is foundfrom the delay time between the transmission and reception waves of thesearch waves.

<Parking or Departing Assistance Process According to SeventhModification Example>

The parking or departing assistance process in the seventh modificationexample is the same as that in the first embodiment, except that theprocess that specifies a stationary object or non-stationary objectaround the target parking region is different.

The parking or departing assistance process in the seventh modificationexample specifies, as a non-stationary object, an object existing at theposition of the difference detected at the processing similar to S26 ofthe first embodiment, and, as a stationary object, an object existing ata position other than the position of the difference. The position ofthe obstacle detected with the ultrasonic sensors 11 is associated withthe position of the difference detected at the processing similar to S26of the first embodiment (i.e., the position in the distance image), onthe premise that both the positions are relative to the vehicle.

The obstacle specification section 70 of the seventh modificationexample detects successively the distance between the vehicle and astationary object or non-stationary object, while executing theabove-mentioned report related process.

<Summary of Seventh Modification Example>

The seventh modification example enables the driver to easily recognizethe presence of a non-stationary obstacle, if present, around a parkingregion even if the host vehicle needs to be close to the non-stationaryobstacle on each parking or departing, similarly to the firstembodiment.

Eighth Modification Example

Another configuration may be provided where the camera 1 is replacedwith a different sensor such as an ultrasonic sensor or radar thatdetects the position of the obstacle relative to the vehicle withtransmission and reception waves of search waves, which may be referredto as an eighth modification example. The case using the differentsensor such as an ultrasonic sensor or radar may use a configurationthat uses the distribution in positions of obstacles detected with thedifferent sensor for the arrangement of obstacle(s), instead of usingthe captured image.

The eighth modification example enables the driver to easily recognizethe presence of a non-stationary obstacle, if present, around a parkingregion even if the host vehicle needs to be close to the non-stationaryobstacle on each parking or departing, similarly to the firstembodiment.

Ninth Modification Example

Another configuration may be provided which differentiates the sensor ina front portion of the vehicle and the sensor in a rear portion of thevehicle from each other such that the ultrasonic sensor 11 is used inthe front portion and the camera 1 is used in the rear portion of thevehicle.

Tenth Modification Example

The above-mentioned embodiment indicates the configuration using theposition detection unit 31 and the map DB 32 in the navigation apparatus3. There is no need to be limited thereto. For example, anotherconfiguration may be provided which uses a position detection unit in aknown locator or a map DB in a server without using the positiondetection unit 31 and the map DB 32 in the navigation apparatus 3.

While the present disclosure has been described with reference toembodiments thereof, it is to be understood that the disclosure is notlimited to the embodiments and constructions. The present disclosure isintended to cover various modification and equivalent arrangements. Inaddition, while the various combinations and configurations, othercombinations and configurations, including more, less or only a singleelement, are also within the spirit and scope of the present disclosure.

What is claimed is:
 1. A driving assistance apparatus used in a vehicle,comprising: a control target detection section that detects as a targetobstacle an obstacle that is existing within a set distance from thevehicle using an obstacle sensor detecting an obstacle around thevehicle; an obstacle handling section that performs at least either areport or an automatic behavior control of the vehicle when the controltarget detection section detects the target obstacle; an arrangementmemory that stores a past obstacle arrangement around a parking regionthat serves as a target; an arrangement acquisition section thatacquires a present obstacle arrangement around the parking region in aparking-region driving operation, the parking-region driving operationbeing at least either a driving operation to cause the vehicle to enterinto the parking region or a driving operation to cause the vehicle toexit from the parking region; and an obstacle specification section thatspecifies a non-stationary obstacle that is an obstacle being notstationary around the parking region, based on a difference between thepast obstacle arrangement stored in the arrangement memory and thepresent obstacle arrangement acquired by the arrangement acquisitionsection, wherein: the control target detection section assigns anon-stationary obstacle with a first set distance as the set distance;the control target detection section assigns a stationary obstacle witha second set distance as the set distance, the second set distance beingsmaller than the first set distance; the control target detectionsection detects as the target obstacle a stationary obstacle when thestationary object is within the second set distance from the vehicle;and the control target detection section detects as the target obstaclea non-stationary obstacle when the non-stationary object is within thefirst set distance from the vehicle.
 2. The driving assistance apparatusaccording to claim 1, wherein the past obstacle arrangement stored inthe arrangement memory and the present obstacle arrangement acquired bythe arrangement acquisition section are acquired with the obstaclesensor used by the control target detection section.
 3. The drivingassistance apparatus according to claim 1, wherein the past obstaclearrangement stored in the arrangement memory and the present obstaclearrangement acquired by the arrangement acquisition section are acquiredwith a different obstacle sensor that detects an obstacle existingaround the vehicle, the different obstacle sensor being different fromthe obstacle sensor used by the control target detection section.
 4. Thedriving assistance apparatus according to claim 2, wherein: the obstaclesensor that acquires the past obstacle arrangement stored in thearrangement memory and the present obstacle arrangement acquired by thearrangement acquisition section is an imaging apparatus; the arrangementmemory stores an image of an area around the parking region capturedusing the imaging apparatus as the past obstacle arrangement around theparking region; and the arrangement acquisition section acquires animage of an area around the parking region captured using the imagingapparatus in the parking-region driving operation as the presentobstacle arrangement around the parking region.
 5. The drivingassistance apparatus according to claim 1, wherein: the arrangementmemory stores a plurality of the past obstacle arrangements according topatterns classified depending on states in the parking-region drivingoperations, respectively; a pattern specification section is included tospecify a pattern among the patterns depending on the states in theparking-region driving operation, respectively; and the obstaclespecification section specifies the non-stationary object around theparking region based on a difference between (i) the present obstaclearrangement acquired by the arrangement acquisition section and (ii) thepast obstacle arrangement according to the pattern specified by thepattern specification section among the past obstacle arrangementsstored in the arrangement memory.
 6. The driving assistance apparatusaccording to claim 5, wherein the pattern is at least one of a directionof the vehicle relative to the parking region, a distance of the vehicleto the parking region, a time zone, or a weather.
 7. The drivingassistance apparatus according to claim 1, wherein: the arrangementmemory stores a plurality of the past obstacle arrangements around theparking region, respectively, according to a plurality of drivers usingthe vehicle, if present; a driver specification section is included tospecify a driver who is driving the vehicle among the drivers; and theobstacle specification section specifies the non-stationary objectaround the parking region based on a difference between (i) the presentobstacle arrangement acquired by the arrangement acquisition section and(ii) the past obstacle arrangement according to the driver specified bythe driver specification section among the past obstacle arrangementsstored in the arrangement memory.